1. Field
The following description relates to a technology for controlling a transfer rate of an Ethernet apparatus, and more particularly, to an Ethernet apparatus having a multiple lane configuration and a method of selectively operating the multiple lanes of the Ethernet apparatus.
2. Description of the Related Art
IEEE 802.3 for a high-speed broadband transmission system supports multiple-lane configuration, as IEEE 802.3 Ethernet standards that support a 40 Gigabit transfer rate and a 100 Gigabit transfer rate. Multiple-lane configuration is a configuration in which multiple lanes having a relatively low transfer rate are used in parallel to one another to form a transmission link with a high-speed transfer rate.
According to IEEE 802.3 standards, a 100 Gb/s Ethernet apparatus is capable of processing data, which is transmitted from media access control layer to a physical layer at a transfer rate of 100 Gb/s, in a distributed manner using ten electrical lanes with a transfer rate of 10 Gb/s or four electrical lanes with a transfer rate of 25 Gb/s. In addition, for a 40 Gigabit Ethernet apparatus, four electrical lanes are assigned between physical coding sub-layer (PCS) and a physical medium attachment (PMA) layer. Such electrical lanes transmit data to corresponding each of multiple optical lanes via PMA layer.
In addition, IEEE802.3 specifies twenty virtual lanes inside PCS layer in an effort to smoothly support the bonding between electrical lanes and optical lanes even if the number of the electrical lanes and the optical lanes are not the same, and specifies a multi-lane distribution (MLD) function block that distributes or bonds 64B/66B coded blocks to the virtual lanes.
Such multiple lanes are adapted for use in transmitting large-capacity data at high speed. There is, however, a case in which temporarily not all bandwidths are required for some particular purposes, for example, for error control, reduction in power consumption or management of array components. For example, if only one of multiple lanes has an error in 100 Gb/s Ethernet system, there is a need of using the rest of the multiple lanes other than the lane having an error. As another example, traffic to be processed by 100 Gb/s Ethernet system is within a rate of several tens of Gb/s, it may need to operate the system to use only some lanes selectively.
In addition, as the data transfer rate increases, power consumption of a communication apparatus rises dramatically. Thus, there is a need for a technology that reduces power consumption in data communication through high-speed Ethernet interface.
IEEE 802.3az Entergy Efficient Ethernet (EEE) standardizes Low Power Idle (LPI) scheme. LPI scheme transmits any data at the maximum transfer rate supported by a transmission link when there is data to be transmitted, and sets the transmission link to idle state (zero transfer rate) when there is no data to be transmitted. In LPI scheme, it is possible to reduce power consumption by inactivating parts of circuits required for data transmission and reception when there is no data to be transmitted.
LPI may be efficient to reduce the energy consumption in transmission of traffic with strong burst properties, but cannot reduce the energy consumption in transmitting streaming traffic which requires continuous transmission service at a low data rate. Furthermore, the technical scope of IEEE 802.3az is to support a transfer rate lower than 10 Gigabit and not to take into consideration a configuration in which a single transmission link, as an Ethernet interface in accordance with Copper physical layer standard, consists of multiple lanes of a low rate.